<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
</head>
<body>

</body>
</html>

<script>
	//var str1 = "100";
	//var str1 = new String(100);
	var str1 = String("100Hello");
	//alert(str1.charCodeAt(3));

	// for(var i=0;i<str1.length;i++){
	// 	document.write(str1[i]+"<br/>")
	// }

	//var supstr = "abcabcabc";
	//alert(supstr.indexOf('abc',4));
	//var newstr = str1.substring(3,6)
	//var newstr2 = str1.substr(3,3)
	// var newstr3 = str1.slice(3,6);
	// alert(newstr3)

	// var str3 = "how are are are you!";
	// document.write(str3.replace(/are/g,"old are"));
	// document.write("<br/>"+str3);

	var str4 = "你好；北京；非常高兴来到这里；上的广告";
	var newarr = str4.split("；");
	document.write(newarr);

	document.write("<br/>"+str1.toUpperCase());
	document.write("<br/>"+str1.toLowerCase());





</script>